As discussed in U.S. Pat. No. 4,998,738 and U.S. Pat. No. 5,112,063, the objective for any hunting arrow with deployable cutting blades is to have the blades retracted to a more aerodynamic position during the flight of the arrow and to have the blades open to a cutting position which causes maximum hemorrhaging when the arrow strikes its quarry. As discussed above, traditional broadheads have fixed, exposed cutting blades which are subject to wind drag and other adverse wind effects during the flight of the arrow. It has been found that broadheads designed with deployable blades overcome the problems associated with wind effects and are more accurate than traditional fixed blade broadheads.
U.S. Pat. No. 2,859,970 discloses a cone which houses a pair of cutting blades therein where the cutting blades are mounted on a pivot pin. The Doonan device is frictionally fit over the tip of a target arrow. The intended design of the Doonan device is such that during the flight of the arrow, the cutting blades stay within the cone, thereby overcoming adverse wind effects on the flight of the arrow. When the cone strikes the animal, the arrow shaft rams the target tip into the back of the cutting blades such that they open up from the cone by pivoting on the pivot pin. One problem with the Doonan device is that the shaft of the arrow is likely to ram the cutting blades of the cone open just as the arrow is shot because of the inertia of the cone relative to the speed of the arrow. Another problem with the Doonan device is that the frictional engagement of the cutting blades against sidewalls of slots in the cone is not easily controllable.
U.S. Pat. No. 4,932,671 shows a phantom bladed broadhead where the cutting blades remain inside a cylindrical ferrule body during flight and are rammed open by a plunger, positioned to slide rearward from the front of the body, when the plunger impacts against the body of the animal. In Anderson, the cutting blades are not connected to the plunger but are pivotally connected to the cylindrical body by a ring which passes through a forward cut out section of each blade.
U.S. Pat. No. 4,504,063 discloses a broadhead which is designed to have a slimmer profile during flight and a wider, cutting profile upon impact. In LeBus, a plunger, which extends from the front of the broadhead while it is in flight, includes a weight at its rear section that acts against notches formed on the inside surfaces of the cutting blades when the broadhead strikes an animal. LeBus utilizes an O-ring to help hold the cutting blades in their slimmer profile during flight wherein the O-ring fits in a notched portion at the base of each cutting blade and the O-ring expands when the weight at the rear of the plunger forces the cutting blades open. Since the blades of the LeBus broadhead are always slightly open, the archer must be very careful when installing the O-ring so as not to get cut on the sharp blades of the broadhead.
U.S. Pat. No. 5,102,147 and U.S. Pat. No. 8,118,694 disclose broadheads having fully retracting blades. U.S. Pat. No. 7,713,152; U.S. Pat. No. 7,905,802; U.S. Pat. No. 8,905,874; and US Patent Application Publication 2015/0184986 disclose broadheads having partially retracting blades. The instant invention is directed at providing a better retractable blade arrowhead having fully retracting blades.